Significant oil leak on V6 TDI engine (engine is leaking)

Hello guys,

Perhaps someone else has encountered this problem before, or maybe someone can offer me some advice. My V6 TDI (AKN) engine has been losing engine oil more frequently lately.

There are increasingly large oil stains appearing underneath the car. My suspicion was a leak in the oil pan. I went to investigate the source of the leak and found that the oil seems to be coming from the top and running down the back of the engine.

There is oil located in the "V", essentially between the two cylinder banks. I wiped it clean, but after a test drive, there was a lot of oil there again.

What could be the problem? Could the lower seal on the oil filter housing be damaged? Has anyone else encountered this error?

I am grateful for any advice.

Regards,
AL

Hello,

It's always difficult to determine the source of a draft because of the airflow, unless you verschandeln everything and do a quick check.

I had the same problem after I removed my head cover. In my case, it was the needle lift sensor. After I had cleaned everything thoroughly and applied sealant to the openings (including the blue semi-circles), everything was sealed again.



But did you already do the pressure test on the oil separator?

Greetings.

Rainer.

Hi,

Okay, so it's not the valve cover gaskets. I've checked them, and they're completely dry all around. I had it resealed a year ago.

But what do you mean by "pressure test of the oil separator"?

Hello.
Okay, please provide the German text you would like me to translate into English.

When a pressure gauge is connected to the oil level indicator pipe, a maximum of 5 mbar can be measured with the engine running. Otherwise, the oil separator for the crankcase ventilation system is either clogged or defective.

If you don't have a pressure gauge, you can also remove the oil filler cap while the engine is running. If you hear a hissing sound, the oil separator is sealed. It's also possible that the overpressure is so low that you can't hear it, but if that were the case, I don't think the oil would be spurting out so vigorously...
Here's the translation:

"By the way, have you ever checked what the oil return line from the turbocharger looks like as it goes into the engine block?" "Something leaked from my car, and suddenly there was no more oil in the engine."

Okay, I just did a quick test. The engine wasn't really warm yet, but when I unscrewed the oil cap, I could hear a distinct hissing sound, so there seems to be some pressure behind it. I'm not sure if that's normal or not.

I've taken a closer look at the engine. It seems that the oil is leaking somewhere in the area of the oil filter housing. The turbocharger pipes are dry.

Regards,
Okay, please provide the German text you would like me to translate into English.

Hello,

The seals on my cylinder head cover are leaking at the injector bore holes. Are the seals available for purchase individually, or would the seller prefer to sell two complete ZKH units?

Otherwise, I replaced the KGE filter as a precaution, but it didn't reduce the oil leak.

Best regards, René.

Hello,

I can only share my experience from my V6 TDI (although it was the AFB engine), which also started to leak oil heavily towards the end. It was coming from all sorts of seals. It started very innocently. First, a tiny amount of oil leaked from a nozzle seal, it was just slightly 'sweaty.' Then, another nozzle on the other cylinder bank started leaking as well. It wasn't too bad yet. One day, I noticed an oil stain under the car. Out of panic, I started searching for the cause. Under the engine cover, everything looked terrible between the cylinder banks. There was a real puddle of oil. Furthermore, oil was leaking from the cable gland of the NHG (likely referring to a specific component), from the valve cover gaskets, and from the oil filter cap. Mostly, the oil was leaking from the valve cover area, spreading across it, and being dispersed by the airflow underneath the entire engine block. I took it to a friendly mechanic and had the crankcase pressure checked. It was above 5 mBar, but not as high as I initially thought; it was around 10-15 mBar. I took it to my independent workshop and had the crankcase ventilation system replaced, and they did a thorough engine cleaning (top and bottom) to ensure it was completely oil-free everywhere. Lo and behold, after the first test drive of about 100 km, almost everything was dry again in the upper area (valve cover gasket and injector gasket). For the first three days, there were no more oil spots under the car. But unfortunately, I was too optimistic; the spots reappeared. I immediately looked at everything up top. But it was still almost completely dry. However, it looked different from below. The oil pan gaskets for both the upper and lower oil pans were leaking. And my mechanic said it looks like something is damp further up (maybe the oil pump?).
Because of that, the car was no longer sufficient for my needs, and I sold it, among other reasons, due to the defect. Replacing the upper oil pan gasket is definitely not a simple or inexpensive job!
I suspect that the excessive crankcase pressure may have damaged the sealant on the oil pan, causing it to start leaking. It's almost like trying to fill a bottomless pit to get a V6 engine completely leak-free again... assuming that's even possible .

I wish you good luck and success. *fg*

Regards,

DENNIS

PS: Now I'm driving another 'small' ASZ and I'm currently experimenting with a resistor instead of the diesel temperature sensor...

That doesn't sound great at all; I don't think an oil filter housing is exactly a bargain.

I'll take everything apart and analyze it next weekend.

Regards,
Okay, please provide the German text you would like me to translate into English.

Don't quote me on this, but I'd say the oil filter housing probably costs around 120 euros.

"In our case, the car came to the workshop, and there was no oil visible on the dipstick. It wasn't easy to locate the leak. At first glance, I would have suspected the turbocharger. The entire top part of the engine was covered in oil. There was about a liter of oil in the oil pan. So, I cleaned it up, refilled the oil, and started the engine. Afterwards, it was very clear how the oil was leaking out from under the oil filter housing." When I turned off the engine, there was a bit of gurgling and bubbling coming from that area.

The ultimate cause was a loose screw and a broken seal. However, the entire housing was replaced as a preventative measure. This turned out to be justified, as a closer inspection later revealed. A hairline crack had formed on the loose screw, barely visible to the naked eye.

The kind man was visibly relieved that this problem could be resolved so cost-effectively, as he had already expected a complete engine failure.

Before you see black, do everything in the correct order.

- Measure the crankcase pressure; if it's too high, replace the component.
( /viewtopic.php?p=65042#65042 )
- Properly verschandeln the engine.
- Take a longer test drive.
-Check after oil leak.
- Seal any leaks.
If you've been experiencing excessively high crankcase pressure for a long time, it's likely that the oil pan and engine case need to be resealed. Unfortunately, it's quite fiddly.

Best regards, Manuel.

PS: When installing a KGE (presumably a type of electrical component), be sure to use the B-variant -> it will provide a permanent solution.
Changing gears for the first time, approximately 3 hours.

Okay, I ordered a new oil separator yesterday. I hope it's the solution. The crankcase pressure is definitely too high in my engine right now. When I open the oil filler cap while the engine is running, it makes a hissing sound.

Now I've also figured out where the oil is coming from. A metal pipe, made of aluminum, runs from the turbocharger down to the engine block (this is the one that looks like an accordion at the bottom), and oil is leaking out of the connection at that point.

Let's see if things get better with the new KGE.

Regards,
Okay, please provide the German text you would like me to translate into English.

Replaced the oil separator yesterday, and also replaced the seal on the oil return line from the turbocharger.

It was a straightforward fix. The built-in oil separator was completely sealed. Now, with the new one, the high crankcase pressure is definitely gone. Okay, I'm going to check now to see if the oil leak has stopped.

Regards,
Okay, please provide the German text you would like me to translate into English.

Okay, I've been driving for about a week now. The engine is completely dry again. Thank you for the tips.

Regards,
Okay, please provide the German text you would like me to translate into English.